Experimental results showed that Q2 gas was adsorbed effectively by CMSB on an early stage of breakthrough even though CH4 exists in the inlet gas. Particularly, in the case of Q2 with low concentration of CH4, the break through curve of Q2 showed almost the same curve as in the case of pure Q2 adsorption. However, CH4 gas spilled over adsorbed Q2 in the course of CH4 break-through. This means that the CMSB will eventually lose the ability to adsorb Q2 in the final stage of adsorption. The critical time when the CMSB loses the adsorption ability depends on the inlet CH4 concentration. Analysis of the results showed that the adsorption of Q2 and CH4 mixture can be roughly described by assuming the multi-component adsorption equations for Q2 and CH4 using Langmuir's equations. It was certified that the analysis model described and predicted the experimental observations very well.